8.14.4 Query Cache Thread States

The server is checking whether the user has privileges to
access a cached query result.

checking query cache for query

The server is checking whether the current query is present
in the query cache.

invalidating query cache entries

Query cache entries are being marked invalid because the
underlying tables have changed.

sending cached result to client

The server is taking the result of a query from the query
cache and sending it to the client.

storing result in query cache

The server is storing the result of a query in the query
cache.

Waiting for query cache lock

This state occurs while a session is waiting to take the
query cache lock. This can happen for any statement that
needs to perform some query cache operation, such as an
INSERT or
DELETE that invalidates the
query cache, a SELECT that
looks for a cached entry,
RESET QUERY
CACHE, and so forth.